The present invention relates to a new and improved pivot joint assembly and more specifically to a new and improved wearindicting pivot joint having a bearing which prevents sidewise movement of a stud while supporting the stud for free rotational and axial movement relative to a housing.
It is frequently desirable to provide a pivot joint having a bearing which will enable a stud to both rotate and/or move axially while retaining the stud against tilting and/or lateral movement even after normal wear has occurred. Joints of this type are useful in applications where tilting and/or lateral motion of the stud is not required or is undesirable. In addition, this type of joint is advantageously used in linkages where due to manufacturing tolerances and other reasons, the distance between two members varies along an axis about which the members pivot relative to each other. Specifically, such a pivot joint is particularly advantageous when used as the non-load carrying pivot joint in the front wheel assembly of a four-wheel drive vehicle.
A pivot joint having an axially movable and rotatable stud in association with the idler arm of an automobile steering linkage is disclosed in U.S. Pat. No. 2,944,829. In the pivot joint disclosed in this patent, a spring acts directly on the stud to retard axial movement of the stud. A head and portion of the stud is pressed against a tapered bearing by the spring. As long as the spring is effective to press the head end portion of the stud against the bearing, the bearing will tend to retard tilting movement of the stud. However, upon the occurrence of axial movement of the stud against the influence of the spring, the bearing is free to become unseated in such a manner as to tend to enable the stud to be moved sidewise or tilted.
Another pivot joint assembly of a somewhat different type is disclosed in U.S. Pat. No. 3,945,737. The stud of the pivot joint disclosed in this patent is held against axial movement by a bearing ring and a bearing cavity end cap or closure disc. Although the stud is urged toward an initial position by a bearing member, the bearing member is composed of a resilient material which enables the stud to be readily tilted upon the application of sidewise forces to the stud. Still other pivot joint assemblies are disclosed in U.S. Pat. Nos. 1,374,267; 1,554,520; 2,241,506; 3,044,798; 3,352,583; 3,361,459; 3,369,848 and 3,434,763.